<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>回调函数</title>
    </head>
    <body>
    <script>
        function a (fn){
            setTimeout(()=>{
                let sum = 10
                fn(sum)
            },1000)
        }

        a((arr)=>{
            console.log(arr);
        })

        //简化抽离
        function b(params){
            console.log(params);
        }
        
        a(b)
    </script>
    </body>
</html>
